GERMINATION. 41 



founded of always producing other micrococci of the 

 same round form. 



For convenience, a common classification of the bacilli 

 is that based upon constant characteristics which are seen 

 to appear in the course of their development under spe- 

 cial conditions — certain of them possessing the power 

 of forming spores, while from others this peculiarity 

 is absent. 



We have less knowledge of the life-history of the 

 spiral forms. Efforts toward their cultivation under 

 artificial conditions have thus far been successful in 

 only a comparatively limited number of cases. Mor- 

 phologically, they are thread- or rod- like bodies which 

 are twisted into the form of spirals. In some of them 

 the turns of the spiral are long, in others quite short. 

 They are motile, and multiply apparently by the simple 

 process of fission.' In most respects, save form and 

 the power of producing spores, they are analogous in 

 their mode of growth to the bacilli. 



The micrococci develop by simple fission. When 

 development is in progress a single cell will be seen to 

 elongate slightly in one of its diameters. Over the 

 centre of the long axis thus formed will appear a slight 

 indentation in the outer envelope of the cell; this inden- 

 tation will increase in extent until there exist eventually 

 two individuals which are distinctly spherical, as was 

 the parent from which they sprang, or they will remain 

 together for a time as diplococci; the surfaces now in 

 juxtaposition are flattened against one another, and not 

 infrequently a fine, pale dividing-line may be seen 

 between the two cells. (See Fig. 1, c and d.) A similar 



1 Dividing into two transversely. 



